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Monday, April 10, 2006

Setting the Odds of Life

(Remember, the upper limit on a statistical probability is 1 over 10^30 to perhaps 10^50. Statisticians do agree that any probability less than 1 over 10^50 is a statistical impossibility.)

It begins, "We evaluate the probability Pr that the RNA of the first cell wasassembled randomly in the time available (1.11 billion years[b.y.]). To do this calculation, we first set a strict upper limiton the number of chemical reactions nr which could have occurredbefore the first cell appeared."

What follows is well explained and the math is presented completely along the way. 47 pages but note that the presenter is a member of The International Society for Complexity, Information, and Design and not a YEC creation scientist per se. Mullan presents standard Darwinist time scales within the context of his work. Yet, he still comes to the same conclusion that I share:

"23. Conclusion

We have numerically evaluated the probability Pr that, in the first1.11 billion years of Earth's existence, random processes weresuccessful in putting together the RNA for the first cell. Inestimating Pr, we initially assumed that the first cell follows therules which guide modern life-forms. That is, we assume there areNaa = 20 distinct amino acids in proteins, and triplet codons inthe genetic code.

In calculating Pr, we consider only the random assembly of RNA: weassume that once the RNA is present, it will generate the proteinsfor the cell. (Thus, we are not requiring that the proteins beassembled randomly: if we were to impose such a requirement, theprobabilities of random assembly of the first cell would be evensmaller than the results we obtain here.) Furthermore, we considera cell which is much smaller than those which exist in the modernworld. The latter contain at least 250 proteins. By contrast, wehave reduced the requirements of the first living cell to a bareminimum: we assume that that cell was able to function with only12 proteins. Compared to the smallest known living cell, ourchoice of 12 proteins seems almost absurdly reductionist. Our"cell" looks more like a modern virus (which cannot reproduceitself) than a bona fide cell. But we proceed anyway.Moreover we also assume that each protein consists of a chain ofno more than 14 amino acids. We refer to this as a (12-14) cell.Again, a chain with only 14 amino acids is considerably shorterthan the smallest known protein in the modern world (whichcontains a few dozen amino acids). It is not clear that a proteinwith only 14 acids would be subject to the 3-dimensional foldingwhich is essential to protein functioning. Nevertheless, we makethese reductionist assumptions about a cell with the aim ofoptimizing the probability of assembling the first cell.

In this spirit, we start with the assumption that the only aminoacids which existed in the primitive Earth were the 20 (or so)distinct types of amino acids which occur in the proteins ofmodern living cells. Also in the spirit of optimization, we assumethat the entire pre-biomass of the Earth was in the form ofproteinous amino acids. We specifically exclude the non-biologicalamino acids (numbering more than one hundred) which may have beenproduced in the primitive Earth. Moreover, we also assume that all20 of the proteinous amino acids were present solely in the Lisomerform so that the growth of a protein chain is not endedprematurely by unintentional inclusion of a D-isomer. Furthermore,we assume that the initial cell occurred in the physicalconditions which are most commonly cited in textbooks, i.e. in a"primeval soup". This allows us to obtain a firm (and generous)upper limit on the number of chemical reactions which could haveoccurred before the first cell appeared on Earth.With all of these assumptions, we find that the probability ofassembling the RNA required for even the most primitive (12-14)cell by random processes in the time available is no more than onein 10^79.

In order to improve on the probability that random processesassembled the RNA for the first cell, we make the (unproven butlikely) assumption that proteins in the earliest cells wereconstructed from a smaller set of distinct amino acids than thosewhich occur in modern cells. In order to ensure that the primitivelife forms had a similar level of error protection in theirgenetic code as that which exists in the modern world, we considera case in which the early proteins consisted of only Naa = 5distinct amino acids. For these, the genetic code can operate withdoublet codons. In such a world, the probability of randomlyassembling the RNA for the first cell in the time available iscertainly larger than in our modern (triplet codon) world. But theprobability is still small, no more than one part in about 10^63.We have identified a region in parameter space where, once thegenetic code exists, the probability of random assembly of thefirst cell could have reached formally large values in optimalconditions. These conditions include the following: (i) the firstcell contained 12 proteins; (ii) each protein in the cellcontained 14 amino acids; (iii) there were 4 bases in DNA; (iv)the protein specificity index was no larger than 2.5 (far belowits average value); and (v) conditions in the primitive prebiospherewere such that chemical reactions occurred at theirmaximum possible rates. (The last of these conditions almostcertainly involves an optimization which is unrealistic by as muchas 10 orders of magnitude.)

(Note that we have said nothing about how the genetic code cameinto existence. We merely assume that it is already in operation.The origin of the code is a more formidable problem than the onewe have addressed here.)

If mathematics were the only consideration, our conclusions wouldsuggest that the RNA for the first cell could have been assembledrandomly in the primeval soup in 1.11 b.y. once there was a codeand abundant supplies of between 11 and 14 distinct proteinousamino acids. However, when we take into account considerations ofcoding theory (especially the necessity to protect the proteinsfrom errors of transcription), it appears that this region ofparameter space is hostile to protein production. And the geneticcode has to pass through a "bottleneck" in order to enter into themodern world, with its 20 proteinous amino acids. As a result, thefirst cell might have had serious difficulties surviving as anautonomous biological system.

Finally, the extreme nature of our assumptions regarding the firstcell (12 proteins, each containing 14 amino acids) can hardly beoverstated. If a cell is to fulfil even the minimum requirementsof a Von Neumann self-replicating machine, it probably needs atleast 250 proteins. Even with multiple optimizations in ourassumptions about the primeval soup, the window of opportunity forcreating such a cell in 1.11 b.y. narrows down to a veryrestricted region in phase space: (I) there must have been exactly 14 distinct amino acids in the cell proteins, (II) the proteinspecificity index must have been between 1.0 and 1.17, and (III)at least 10^58 chemical reactions must have occurred between thebases (or amino acids) in 1.11 b.y. The "fine tuning" of suchconditions presents a problem. However, there are more seriousproblems than fine tuning: error protection in the genetic codefails altogether in these conditions. Even the Central Dogma ofbiology breaks down. A cell formed under these conditions wouldtruly be subject to serious uncertainties not only during day-todayexistence but especially during replication. The cell couldhardly be considered robust.

Nevertheless, as Yockey (p. 203) points out, the possibility thatan organism from the doublet-codon world might have survived the"bottleneck" may have some empirical support. According to theendosymbiotic theory (L. Margulis 1970, Origin of Eukaryotic Cells, Yale Univ. Press, New Haven CT), mitochondria might havebeen at one time free-living bacteria which now survive in asymbiotic relationship with the cytoplasma of other cells. Inmitochondria, the genetic code differs somewhat from the code inother cells. Perhaps mitochondria are representative of organismswhich originated in the doublet-codon world, but which could notsurvive on their own because of the difficulties associated withthe hostile zone of parameter space where they originated.In summary, if the first cell actually originated by randomprocesses, the genetic code must already have existed, andconditions must have been "finely tuned" in order to trace a paththrough a narrow (and hostile) region of parameter space. The ideathat some of the constants of the physical world have been subjectto "fine tuning" in order to allow life to emerge, has been widelydiscussed in recent years (e.g. in the book by J. D. Barrow and F.J. Tipler, The Anthropic Cosmological Principle, Oxford UniversityPress, 1994, 706 pp). If we are correct in concluding that "finetuning" is also required in order to assemble the first cell, wemight regard this conclusion as a biological example of theAnthropic Principle."

In a side note, you will notice that no Darwinist has been able to claim The Origin-of-Life Prize ® as posted on the internet.

""The Origin-of-Life Prize" ® (hereafter called "the Prize") will be awarded for proposing a highly plausible mechanism for the spontaneous rise of genetic instructions in nature sufficient to give rise to life. To win, the explanation must be consistent with empirical biochemical, kinetic, and thermodynamic concepts as further delineated herein, and be published in a well-respected, peer-reviewed science journal(s).

The one-time Prize will be paid to the winner(s) as a twenty-year annuity in hopes of discouraging theorists' immediate retirement from productive careers. The annuity consists of $50,000.00 (U.S.) per year for twenty consecutive years, totalling one million dollars in payments."

Umm, we didn't just want any old equations, but the equation and assumptions behind the claim re. horse evolution you've made repeatedly. What we have here is an ID paper about abiogenesis. Yes, it has lots of numbers, but it's a completely different subject from what you claimed.

Where are the equation and assumptions behind the horse evolution odds claim?

"47 pages but note that the presenter is a member of The International Society for Complexity, Information, and Design and not a YEC creation scientist per se."

... which is the ID think tank co-founded by William Dembski. I'm not sure why you think the lack of YEC hands on this should be all that significant. Less chance of intellectual dishonesty? Could be, I suppose.

I have a better offer for you. The first person to deliver conclusive empirical evidnce for a global flood destroying all life on earth 6000 years ago, and have it published in a well respected peer reviewed scientific journal, will not only get millions in grant money to further their research, they will win the Nobel Prize on top of it. Guaranteed. Any takers?

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